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VACUUM FORMING Project 005

 

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Project 005 Wing Camera Housing for Radian Glider

I wanted to mount my wing camera on an aircraft that did not have any vibration in a way where the image did not have a propeller in it. I chose to try mounting it half way out on the wing of my Radian Pro glider. I also wanted to angle the camera so that the horizon was just below the top of the frame so that most of the image was the ground.

 

Here are the camera and the plane.

 

HD Wing Camera (RD32)

Radian Pro Glider

 

The angle of attack of the wing is 3o, so the cord of the wing is 3o to the horizontal. The housing is angled at 17o relative to horizontal (20o relative to the wing cord). The cameras vertical range of view is 54o. This puts the top of the camera frame at 10o above the horizon when the plane is flying level.

Making the Moulds

 

 

The contour of the top surface of the wing was plotted using the jig shown here on the left.

 

 

Points were plotted on a graph every 5mm over the front part of the curve, then 10mm for the rest.

 

This curve is cut out and traced onto the sides of a block of pine wood. The top of the block (A) was cut along the curve.

 

 

The block (A) is then cut along the centre and a block shaped to the size of the camera (B) is placed in the centre. These three blocks are secured to a base board (C) made from 4mm thick three ply sheet. The gaps are filled with wood filler, the surfaces are coated with a thin coat of wood filler and then filed and sanded smooth.

At the corner where block B joins with blocks A, holes are drilled down to the base. In the base there are cavities made to allow the vacuum to draw air from the internal corner between the blocks so atmospheric air can push the sheet well into the corner during forming.

The sides of each A block are cut at an angle (D) to allow easier removal of the mould from the formed part after forming.

A separate block to form the shelf is also prepared.

Making the Housings

 

 

The parts are formed from 0.5mm HIPS. After forming, the edges are trimmed with scissors, the holes are cut with a scalpel and filed smooth with needle files. The shelf is glued into the housing. 3mm diameter holes are punched on the flange around the housing. A second housing is made for the other wing to house a counter weight so the plane remains balanced. The counter weight is made from a bolt cut to a length to create the required weight and inserted into a block of balsa. A flap of reinforced tape forms a hatch. A triangular piece of polystyrene foam attached to the tape holds the camera or counterweight in place.

 

Attaching the Housings to the Wings

The housing is placed on the wing and the holes are marked on the wing. Holes are drilled in the wing and 12mm long threaded nylon standoffs are imbedded into the wing and glued using epoxy glue. The bottom of the standoffs are blocked with PVC tape to prevent glue rising up in the centre of the standoff. The six sides of each standoff are roughened with a file before gluing them into the wing.

Nylon 3mm screws are then used to screw the housing to the wing.

 

 

The housings are placed far enough out on the wings so that the wide angle lens does not see the propeller.

 

 

The camera and counter weight each weigh 37gm. The housings each weigh 4gm.

The total weight of both housings, camera, counter weight, nylon standoffs and nylon screws is 86gm.

 

To provide stability to the glider, a gyro is installed to control the ailerons. The glider then self corrects when buffeting would otherwise cause the glider to roll. (I would add a gyro to the elevator and rudder too but there is no room left in the plane!)

Video

This video shows a flight of the Radian Pro with the wing camera mounted on the wing.

There is a bit of vibration while the motor is running during the ascents, but otherwise the flight is as smooth as the capability of the pilot would allow!

 

The video is here.

https://www.youtube.com/watch?v=Ys-B9st9yLc

 

 

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